Improvement in slides for extension tables



anatema'.

y struPlinnl srIjnWELL, or WATERLOO, New YORK.

Letters PctentNo.107,63@datecl`-Septmaber 20, '1870i rMPRovEMENT IN saxons Foa vEzrtiteivsrolv trannies;A

The' `Schedule referred to in these Letters Patent; and making part'of-the same.

"I, STEPHEN STILWELL, of Waterloo, iu thecounty `of Seneca and State of New York, have invented cer-` tain Improvements in Slides `for Extension Tables, of

which the following is a specification.

"The slide-bars `of extension tables, as' heretofore constructed, are connectedztogether by Arigid dovetail' couplings, which slide in a-groove'or grooves in the contiguous facesof thebars, l

The expansion and-,contraction of the barscause `this dovetail connection in the one case, to bind', soa's torenderthe operating ofthe bars quite ditticult,

whilejin the other an objectionable looseness in thev connection results.`

h. The` chief object of my improvements isto prevent these objectionable results; and f rIhe invention ,consists-` First, inthe use, or employment of aspriug or elastic coupling foiconnectiug ,the extension. bars,

`which will yildwith theexpansion and lcontraction of the bars, so as to` insuiea,uniformA connection'that, shallbe suiiciertly tight to prevent rattling or objectionable play, andloose enough ,to enable the bars to be readily extended and contractedwithout bind- Secondly, lcfa `do'v'etail for connecting `the ex- 1 tension-bara'inade. in` two fpartswhen these parts are unitedby' ascewprovided with a `rubber washer under its head, or their equivalentgwhiclrpermitsthe parts to expand'andcontract 'as required:V

Thirdly,in 'reducing thewkey orfeather which projectsifronl, the face of 'onejoffthe extension bars into the groove of the contiguous bar, in' which* it slides on the upper side only, so asfto leaveanairow space l between it` and the uppersideof the groove, vwhich a Linsuresthe free and unobstructed movement of the key therein, and its expansion and contraction, 'when made, of.wood, without the bars sagging at the center, as they are. liable to do.

l a In the accompanyingdrawing-L Figure I is a cross-section ot'` three extension bars providedwith myrnprovernents. `Figure II is a'faceviewof a portion of one bar,

`chewing' avsectionof the stop-pins coupling-slide of the contiguous bar.,

Y Figure III is -a"iongitudinal section on a reduced scale;` I

` Like letters of reference designatelike parts inr each ofthe figures. y l. 1

A A1 A2 represent three slide-bars of au extension a, a central longitudinal groove,lformedin the ad- A jacent faces of each, made'of any suitable form to re*-- ceive the dovetail key orslide, which connects them together. y x h B represents such key or coupling, oneof which is shown in section in Fig. I, with one of its edgesl fast` erred in the slide A1, while the other projects .andl slides'in the groove in the bar A.

To this projecting edge I attach aplate, ,0, of

. metal, which projects beyond the edges o'f the key B,

so as'to forin the wings of the dovetail, by which the two bars are held Vvtogether, against lateral, displacement.

Y This plate C I provide with one or more holes, c,

` countersunk-attheir edges, so as to receive the. head of the 'screw or screws d, by which -it is fasten-ed to ,the key or feather B.

Under the head of this screw, inthe countersink, I arrange a spiralspring or rubber washer, e, of vsufhcie'nt thickness to render the fastening a yielding one,

so that the plate CcanJ-ield as the wooden bars contract or expand under the different degrees of moistV ure of the atmosphere, thereby ,insuring a .uniform A pressure between the contiguous faces of the bars under all circumstances, and a consequentuniformity in the operation thereof. l -It is evident that the coupling B C may be con- -structedin various ways,4 and still beelastic, so as to accomplish the same desired result, viz., the yielding l of the coupling as the extensionffbars expandV and con# tract.

Heretofore, Vto insure the free movement of the guide or feather B in the groove of the bar, the portion of the former which projects therein has been slightly reduced in thickness from both sides thereof. This Inode ofdconstructiou has rendered it difficult to sufliciently'rfeduce the'siyze of the feather to enable it to slide freely without the bars sagging at the center when extended. Y Y By making this reduction from the upper side'only, 'as shown at 'i if, this liability ot'4 the bars sagging is avoided, as the bearing of the grooves of the bars comes on the under side only of the slides, as clearly shown in Fig. II, whereby that nicety of adjustment heretofore required isdispensed with, as a greater 'er lesser space can be leftfbetween the upper edge of V bars.-

H H are the longitudinal grooves or depressions in the adjacent faces of the bars, which are so made as to leave the bearing lor surface of contact between thel twg bars only along the edges, as shown at h, which small surface can be kept easily lubricated, sov as to insure the sliding of the bars with the'least 'possible friction and 'liability of binding.

This construction enables the 4stop-pins m Am. to be arranged in` said grooves for the purpose of arresting the movement of the bars, and preventing the undue extension thereoas clearly shown in the drawing.

What I claim as my .invention is- 1. Thecoxnbination, with the slide-bars of mi cxtenson table, of an elastic coupling or connection, which'will yield with the contraction and expansion of the bars, substantially as hereinbefore set forth.

2.v The combination, with the extension bars A A?, the parts B C of :t clovetail coupling, and the screw (7,

of the rubber washer and spring e, arranged with the latter, und operating as hereinbefore set forth.

3. The rebate i, made in the upper side only of the feather or key B of n. coupling for extension bars, us and for the purpose herenbefore shown and described. l

Witnesses: STEPHEN STILWELL.

DANIEL H. BERRY, J. K.A RICHARDSON. 

